#include <iostream>
#include <string.h>
#include <vector>
#include <cstdlib>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <functional>
#include "Task.hpp"
#include "Channel.hpp"

using work_t = std::function<void()>;

enum
{
    OK = 0,
    UsageError,
    PipeError,
    ForkError
};

class ProcessPool
{
public:
    ProcessPool(int n,work_t w)
        :processnum(n),work(w)
    {

    }
    // work_t : 是回调方法
    int InitProcessPool()
    {
        for (int i = 0; i < processnum; i++)
        {
            // 1.先有管道
            int pipefd[2] = {0};
            int n = pipe(pipefd);
            if (n < 0)
            {
                return PipeError;
            }
            // 2.创建进程
            pid_t id = fork();
            if (id < 0)
            {
                return ForkError;
            }
            // 3.建立通信信道
            if (id == 0)
            {
                close(pipefd[1]); // read
                // child
                dup2(pipefd[0], 0);
                work();
                exit(0);
            }
            // 父进程执行
            close(pipefd[0]); // write
            channels.emplace_back(pipefd[1], id);
        }
        return OK;
    }

    void DebugPrint()
    {
        for (auto &c : channels)
        {
            std::cout << c.Name() << std::endl;
        }
    }

    void DispatchTask()
    {
        // 2.派发任务
        int who = 0;
        int num = 20;
        while (num--)
        {
            // a.选择一个任务,整数
            int task = tm.SelectTask();
            // b.选择一个子进程channel
            Channel &curr = channels[who++];
            who %= channels.size();
            std::cout << "#######################" << std::endl;
            std::cout << "send " << task << " to" << curr.Name() << ", 任务还剩: " << num << std::endl;
            std::cout << "#######################" << std::endl;
            // c.派发任务
            curr.Send(task);
            sleep(1);
        }
    }

    void CleanProcessPool()
    {

        //v2
        // for (int i = channels.size();i >= 0;i--)
        // {
        //     channels[i].Close();
        //     pid_t rid = waitpid(channels[i].Id(), nullptr, 0);
        //     if (rid > 0)
        //     {
        //         std::cout << "child " << rid << " wait ... success" << std::endl;
        //     }
        // }

        // v1
        for (auto &c : channels)
        {
            c.Close();
        }
        for (auto &c : channels)
        {
            pid_t rid = waitpid(c.Id(), nullptr, 0);
            if (rid > 0)
            {
                std::cout << "child " << rid << " wait ... success" << std::endl;
            }
        }
    }
private:
    std::vector<Channel> channels;
    int processnum;
    work_t work;
};